铂类抗癌药细胞药代动力学及与药效特异性的相关性研究

Nowadays, platinum anticancer drugs are used widely for the powerful antitumor activity. Therefore, it is quite meaningful in theory and practice to do research on their mechanism of action. In our team, results revealed that in the early stage, though the pharmacokinetic behavior is similarity, each one has specifically clinical indication. This indicates that the concentration of platinum in blood and tissue with classical pharmacokinetic can not reflect the cytotoxicity of drugs. With the deformation of DNA chain by cross-linking, platinum drugs can play an efficient role against cancer through acting on intracellular targets. For these reasons, it is of great significant to clarify the disposal rules of platinum drugs within cells. Cellular pharmacokinetics, regarding cells as a micro organism, is used to study the dynamic changes of drug inside the cells. And combining with pharmacodynamics research, it can be more accurate evaluate intracellular targeting property and material action basis of drugs. In this project, we plan to do research on speciation analysis of platinum through HPLC with inductively coupled plasma mass spectrometry and separate subcellular structure by differential centrifugation. Then, in a series of cancer cells, we will define the dynamics process of absorption, transformation and distribution of different platinum anticancer drugs. Furthermore, the relationship between dynamics behavior and cytotoxic in cancer cells will be revealed through intercellular pharmacokinetic and pharmacodynamic (PK-PD) model. Thus, we can not only be able to reveal the mechanism of action of platinum anticancer drug in a new way, but also provide reference for development of novel platinum antitumor drugs.

铂类抗癌药因抗癌活性强而得到广泛应用。不同铂类抗癌药药动学行为相似，但临床却各有适应症。这意味着经典药动学所检测的血浆及组织中铂元素的浓度不能真实反映药物的细胞毒作用，使用经典药动学理论与方法研究铂类金属抗癌药物药动学存在一定的局限性。铂类药物作用靶点位于细胞核，其跟 DNA 链交联导致形变产生抗癌作用。因此研究铂类药物在细胞内的处置规律具有更实际的意义。细胞药动学将细胞看作一个微观有机体研究药物在细胞内的动态变化规律，将其与药效学研究结合可更为精准地评价药物的靶向性及物质作用基础。本项目拟采用高效液相－电感耦合等离子体质谱技术进行铂形态分析，采用差速离心法实现亚细胞分离，研究新型铂类抗癌药在系列癌细胞内摄取、形态转化及分布的动力学过程，建立细胞内药动学－药效学结合模型，探讨癌细胞内动力学行为与细胞毒之间的相关性，为揭示铂类抗癌药物作用机制提供新的思路，也为新型铂类抗癌药的研发提供参考。

顺铂、卡铂、奥沙利铂分别是第一、二、三代铂类抗肿瘤药物，因其抗癌活性强，在临床上得到广泛的应用。普遍认为他们具有相似的作用机制，均作用于细胞核内的DNA,抑制DNA复制，从而导致肿瘤细胞凋亡。然而，其临床适应证各有侧重点，毒副作用也各异。铂类药物进入体内后会发生一系列的复杂转化，至今其药效和毒性机制尚未完全阐明清楚。本研究首先从铂类药物的形态分析入手，成功建立了三种经典铂类抗癌药顺铂、卡铂、奥沙利铂在全血、血浆、和血浆超滤液中的原药定量方法，同时也建立了总铂元素定量的ICP-MS分析方法，并运用已建立的方法分别从体外和体内水平上，首次从铂原药和总铂元素两个形态系统比较了三种铂药物在大鼠血液的药代动力学及分布规律，揭示了仅仅用铂元素进行定量表征铂药物的药代与药效动力学具有一定的局限性。进一步运用细胞药代动力学研究手段，从微观的细胞和亚细胞水平首次探讨了铂药物在细胞内的吸收、累积、分布和消除等特征，结果表明铂原药在细胞内生物转化迅速，主要以含铂转化物的形式存在，细胞内总铂在各亚细胞器的分布存在明显差异，胞浆高于线粒体，高于细胞核，铂原药和含铂转化物在线粒体的富集可能会影响线粒体呼吸链和能量代谢及其代谢产物，线粒体可能是铂药物药效与毒性的另一潜在靶点。同时，我们探究了铂药物对癌细胞的细胞毒与细胞药动之间的相关性，并发现细胞内铂药物的摄取量与细胞毒之间存在一定的相关性。.本研究成功攻克了铂原药定量分析的技术难关，开发了顺铂、卡铂、奥沙利铂的高灵敏度定量分析方法。并将该原药分析方法与总铂ICP-MS定量方法同时使用，分别从原药和总铂两种形态角度，首次系统研究了铂药物在体内血液药动学规律和细胞药动学规律，为揭示铂类抗癌药物的药效和毒性作用机制提供了重要理论依据，同时也为新型铂类抗癌药的研发提供新思路。